Inductance clip



July 27, 1948. J. F. FRESE INDUGTANCE CLIP Filed Dec. 20, 1944 Mow;

III: Q11

/4a il I Patented July 27, 1948 UNITED STATES PATENT OFFICE INDUCTANOE CLIP Application December 20, 1944, Serial No. 569,053

Claims. 1

My invention relates broadly to electrical connectors and more particularly to an electrical connector for high frequency electrical circuits.

One of the objects of my invention is to provide a construction of electrical connector having means for establishing firm electrical connection with inductance coils carrying high frequency electrical current where the connection may be readily adjusted to accurately establish a tap at a required electrical circuit position in the inductance.

Still another object of my invention is to provide an improved construction of inductance clip for establishing an adjustable connection with a strip-like inductance coil in which a tap may be established either inside or outside the inductance coil, the connection being such that very substantial surface contact is established with the coil whereby rated load may be carried Without excessive heating,

Still another object of my invention is to provide a construction of inductance clip for edgewise wound high frequency inductance coils in which cam members carried by one portion of the clip coact with cam members carried by another portion of the clip for effectively clamping an edgewise wound strip between the portions of the clip for establishing substantial electrical and mechanical connection between the clip and the inductance.

Still another object of my invention is to provide an improved construction of inductance clip having a pair of coacting parts adapted to effect a wedgewise connection with a ribbon-like strip in which the coacting parts have cam-like portions operative one with respect to another for effectively clamping the ribbon-like strip and wherein the metal in one portion is displaced to provide an enlarged current carrier through a screw-threaded connection for screw-threaded connecting means extending through the coacting portions of the clip for increasing the current carrying capacity and mechanical strength of the clip.

Other and further objects of my invention reside in the improved construction of adjustable clip for high frequency inductance coils as set forth more fully in the specification hereinafter following by reference to the accompanying drawings in which:

Figure 1 illustrates a high frequency inductance showin the inductance clip of my invention applied to one of the edgewise wound turns thereof and extending inwardly toward the interior of the coil and enabling the tap on the inductance coil to carry rated load without excessive heating; Fig. 2 is a side elevational view of the clip illustrated in Figure 1 taken on section line 22 through the turn. of inductance with which the clip is associated; Fig. 3 is a side elevational View of the inductance clip on a somewhat enlarged scale and showing the coasting cam-like portions of the inductance clip and the manner in which the coacting cam-like portions enable the edgewise strip to be effectively engaged by the inductance clip; Fig. 4 is a cross-sectional View taken on line 4-4 of Fig. 1 on a somewhat enlarged scale and illustrating the cam-like portions of the inductance clip in position and gripping an edgewise wound strip constituting a turn of the inductance; Fig. 5 is a transverse sectional View through the inductance clip taken on line 55 of Fig. 4'; Fig. 6 is a transverse sectional view through the inductance clip taken on line 6-6 of Fig. 1-; Fig. '7 is a vertical sectional View taken on line 1-1 of Fig. 3 and illustrating the inductance clip in elevation; Fig. 8 is a perspective view showing the cam-like portions of one of the parts of the inductance clip; Fig. 9 is a perspective View of the other of the coacting portions of the inductance clip, the two Figs. 8 and 9 being shown in spacial relation for the purpose of illustrating the manner in which the cam-like portions interengage toeffect connection with an inductance strip; Fig. 10 is a, perspective view of a portion of the part of the inductance clip illustrated in Fig. 8, the view showing the manner in which the metal is displaced centrally for increasing the effective thickness of the screw-threaded portion of the inductance clip for providing a path of increased electrical conductivity and of greater mechanical strength; and Fig. 11 is a theoretical view showing the arrangement of the coact'ing cam-like portions on the two parts of the electrical connector constituting the inductance clip.

My invention is directed to an improved construction of inductance clip in which an adjustable connection may be made to the oscillation tank circuit or other circuit of inductance coils. In adjusting such equipment it is often necessary to shift the tap or taps on the inductance coils and it is often desirable that the taps may be taken from the inside as Well as from the outside of the coils. The clip of my invention is very effective on edgewise wound inductance coils for making good and firm surface contact with the coils and carrying rated load without excessive heating. Flat clamping strip-like jaws resembling the jaws of a knife switch have proven unsatisfactory in that excessive tightening of the 3 clamping screws often bends the clamping strip rendering the strip unusable after a short time as such strip becomes loose and introduces circuit inaccuracies and heating. Different sizes of metallic ribbon are used in winding high frequency inductance coils. Such coils vary in size from approximately four inches to ten inches in diameter and consist of ribbon of various widths and thicknesses, such as to wide and from 3 g to thickness having square or round edges. When the inductance coils are edgewise Wound the thickness changes, becoming thicker at the inside diameter and thinner at the outside diameter. The clip of my invention is intended to meet many variable conditions which are found in the art for establishing good electrical connection with an inductance strip within wide limits irrespective of width and thickness of the strip. I provide tWo coacting jaw members each having cam-like portions thereon interengaging with each other and operative to embrace opposite sides of the inductance strip with which adjustable connection is to be established. One of the jaw-like strips has the metal thereof centrally displaced for effectively enlarging the strip in that portion through which a securing screw must pass in clamping the jaw-like parts against opposite sides of the inductance strip. Thus firm mechanical connection and good electrical connection is established between the clip and the inductance strip.

Referring to the drawings in more detail reference character I indicates in cross-section the refractory members of the frame support for a high frequency inductance system where the refractory members are radial as represented at la for receiving the edgewise wound metallic striplike coil indicated at 2. The turns of the striplike coil 2 are sufficiently spaced to allow a tap connection to be made therewith by means of the inductance clip of my invention.

The inductance clip comprises a pair of clamping members 3 and I each extending substantially co-planar with the opposite sides of the inductance strip 2 and interconnected by means of fastening screw 5. Fastening screw 5 passes through a lock washer 6 arranged immediately beneath the head thereof and extends through an elongated slot l provided in clamping member l and through the centrally displaced and screwthreaded portion 3 of the clamping member 3.

The displaced portion 8 of clamping member 3 forms one of the important features of my invention. A relatively narrow centrally elongated zone of clamping member 3 is displaced through a die having a pair of parallelly extending anvil faces which confine the displacement of stri 3 to a zone between the flats 8a and 8b. This results in densing the metal in the area of displacement for eifectively increasing the depth of the metal through the transverse zone represented at 3:1 in Fig. 6. This increased depth of the metal provides for a larger number of screw threads represented at 9 in Fig. 10 thereby substantially increasing the electrical conductivity and mechanical strength through the connection of the screw threads of the fastening screw 5 with the screw threads 9. The displacement of the metal in the zone 8 results in shallow elongated cup-shaped recess 80 on the inner face of the clamping member 3 and an elongated protuberance 801 on the opposite side of the clamping member 3.

Clamping member 3 is provided with a hookshaped end i6 arranged to engage over the edge the plane of the clamping member 3 and have their inner faces parallel and aligned with the opposite edges of the clamping member 3. The edges Ma and lfa of the side portions ii and I2 remote from the screw-threaded portion 9 are normal to the plane surface of the clamping member 3, whereas edge portions Hb and l2b of the side members i l and I2 immediately adjacent the screw-threaded portion 9 are cam shaped and disposed on an angle of substantially 45 degrees. The depth or projection of the side portions H and i2 is sufiicient to fully embrace the opposite edges of the clamping member l which is centered therebetween as the clamping member 4 is adjusted to clamp the inductance strip 2.

The clamping member a has a pair of side members i i and l 5 extending in planes normal to the plane of the clamping member l and coextensive with the opposite edges thereof in positions operative to engage at one end the edge of the inductance strip 2 and at the other end the cam-like edges ill) and I21) of the projecting portions l l and i2. The members M and it have edges shaped in composite contour, the edge immediately adjacent the inductance strip 2 being formed on an angle of substantially 3 degrees as represented at Ma, the remote edge l lb being substantially parallel to the plane of the clamping member t and the cam-like edge l lc being formed on an angle of substantially 50 degrees with respect to a line 3d extending normally to the plane of clamping member 3. Similarly the side portion l5 has the edge faces thereof formed as represented at a, 55b and I50.

The cam-like faces lie and Ill) and the cam faces [50 and lib slide with respect to each other as the clamping screw 5 is adjusted to draw the clamping members 4 and 4 together against opposite sides of the inductance strip 2. By providing the cam members [4 and i5 with cam faces Me and I50 of greater pitch than the cam faces llb and I21) on cam members I l and I2, the displacement of clamping member 4 Within the limits allowed by slot 7 in the direction of the edge of the inductance strip 2 is facilitated. The inductance strip 2 is engaged beneath the extremity 4a of clampin member 4 and wedged against the cam faces Ma and Mia of the clamping member 4 which force the inductance strip 2 against the hook-shaped end ill of the clamping member 3.

Thus a firm electrical connection may be established with the edgewise wound turn of inductance at any selected position with minimum losses in the conduction of high frequency electrical current, The clamping member 3 is bent at an angle to the plane thereof as represented at It and is suitably apertured at l! to receive a suitable binding post or securing screw and nut assembly represented at ill for completing connection between the high frequency conductor l9 and the inductance clip. As illustrated in Figure 1 the connection to the inductance may be made at a position interiorly of the inductance coil.

in order to change the setting of the inductance clip with respect to the turn of the inductance, it is only necessary to loosen clamping screw 5 and slide the inductance clip to the desired position and again tighten the clip in the desired setting.

In general the protuberance in zone 8 that is formed in the flat metal 3 operates to:

l. Stifien the inductance clip so that it will not bend when the screw 5 is tightened; thi is most important because heavier sheet metal cannot be used because it would seriously cut down clearance between turns.

2, Provide a greater number of screw threads for increasing the physical strength of the connection.

3. Provide greater conductivity around the screw.

I have found the inductance clip of my invention highly efiicient in operation and as providing means for establishing connection with high frequency inductance units with minimum high frequency losses and without excessive heating at rated loads.

While I have described my invention in one of its preferred embodiments I realize that modifications and changes may be made and I intend no limitations upon my invention other than may be imposed by the scope of the appended claims.

What I claim and desire to secure by Letters Patent of the United States is as follows:

1. An inductance clip comprising a pair of clamping members operative to engage opposite sides of an inductance strip, one of said clamping members having a hook-shaped end engageable with one edge of an inductance strip and having a pair of side members extending substantially normal to the plane of said clamping strip coextensive with portions of the opposite edges thereof, said second clamping member having a portion thereof extending between the side portions of said first mentioned clamping member and having integrally connected side members coextensive with portions thereof and projecting toward the side members of said first mentioned clamping member in planes substantially coincident with the planes of the side members of said first mentioned clamping member and screw means extending through said clamping members for forcing the side members of said second mentioned clamping member into engage ment with the side members of said first mentioned clamping member for eifecting an endwise movement of said second mentioned clamping member with respect to said first mentioned clamping member for wedging the inductance strip between the hook shaped end of said first mentioned clamping member and the side members on said second mentioned clamping member,

2. An inductance clip comprising a pair of clamping members engageable with opposite sides of an inductance strip, a hook-shaped end on one of said clamping members engageable with one edge of the inductance strip, a pair of spaced cam members integrally connected with :portions of said last mentioned clamping member remote from the hook-shaped end thereof and a contact face on said member for establishing surface contact with One face of the inductance strip, said second clamping member having a contact face engageable with the opposite face of the inductance strip and having the other end thereof slidable between the spaced cam members on said first mentioned clamping member, a pair of coacting cam-like members carried by portions of said last mentioned clamping strip in edge-toedge alignment with the cam members on said first mentioned clamping strip and screw means extending through said clamping members for forcing said coacting cam-like members into engagement for advancing the cam members on said second mentioned clamping member against spaced intervals along the inductance strip confined against the hook-shaped end of said first mentioned clamping member.

3. An inductance clip comprising a pair of clamping members engageable with opposite sides of an inductance strip, one of said clamping members being centrally screw-threaded and provided with a hook-shaped end engageable with one edge of the inductance strip, cam-like members coextensive with a portion of the edges of said last mentioned clamping member, the second of said clamping members having a longitudinally extending slot therein, screw-threaded means xtending through the slot in said second mentioned clamping member and engaging the screwthreaded portion of said first mentioned clamping member, cam-like members coextensive with portions of the edges of said second mentioned clamping member and directed toward the camlike members of said first mentioned clamping member, the faces of the earn-like members on said first mentioned clamping member being formed on an angle of substantially while the faces of the cam-like members on said second mentioned clamping member are formed on an angle of substantially said cam faces moving with respect to each other as said screw-threaded means is adjusted to clamp said clamping members on opposite sides of the inductance strip for gripping the edges of said inductance strip between the hook-shaped end of said first clamping member and the cam members on said second clamping member.

4. An inductance clip comprising a pair of clamping members engageable with opposite sides of an inductance strip, one of said clamping members having a hook shaped end and having a central longitudinal portion thereof outstruck to form a protuberance having an effective depth greater than the thickness of the clamping member, said protuberance being centrally screwthreaded for receiving a greater number of screw threads than would normally be received directly through said clamping member, cam-like members coextensive with portions of the opposite edges of said clamping member, the second clamping member extending between the cam-like members on said first mentioned clamping member and having cam-like members coextensive therewith, with the faces thereon slidable on the faces of said first mentioned cam-like members, a screw device extending through said second mentioned clamping member between the camlike members thereon and engageable with the screw threads in said protuberance whereby said clamping members are adjustably secured in mechanical and electrical connection with the inductance strip extending therebetween and with the hook shaped end of said first mentioned clamping member engaging the edge of the inductance strip.

5. A clip for connecting an edgewisewound electrical coil to another conductor comprising a strip of fiat metal establishing surface contact with said edgewise wound coil and having a hook at one end adapted to engage the one edge of the coil, said strip having cams at its edges spaced from said hook, a clamping member comprising a relatively flat metal strip clamped against the 7 opposite surface of said coil in coaction with said first-mentioned strip and having cams at its side edges sloping oppositely from the cams on said strip and slidably engageable edge-to-edge therewith for effecting clamping engagement between each of said last-mentioned cams and the other edge of said coil and means for drawing said strips together with said coil therebetween.

JOSEPH F. FRESE.

REFERENCES CITED Number UNITED STATES PATENTS Name Date Matthes Feb, 12, 1929 Frese May 18, 1937 Frese May 18, 1937 Dibner June 6, 1939 Thomas, Jr. et a1, June 18, 1940 Jagger et a1 July 15, 1941 Pieper Dec. 29, 1942 

